Mammals are the most developed animals.

• Like birds they are warm blooded.
• They have efficient respiratory and circulatory systems.
• They have well developed senses.
• Brains enable adapting to different circumstances.
• Many mammals can learn new things quickly.

Mammals are characterized by the presence of mammary glands in females. A new individual develops in the uterus of the female. After birth, females use their mammary glands to breastfeed their young. 

Mammals are found everywhere on the planet. Most known orders of mammals are Chiroptera (bats), the Cetartiodactyla (whales and even-toed ungulates = the animals with hooves), the Carnivora (cats, dogs, seals, and others), the Rodentia (mice, rats and other gnawing mammals) and primates (apes, monkeys, and others).

List of mammal genera